388 ASCORBIC ACID 



requirement presumably is increased. (2) It may necessitate the mainten- 

 ance of a blood level of ascorbic acid sufficiently high to stimulate phago- 

 cytic activity. A possible method for determining this type of requirement 

 is suggested by the studies of Nungester and Ames.^^ Under their exper- 

 imental conditions a serum level of approximately 0.4 mg. % of ascor- 

 bic acid was necessary to provide a high degree of phagocytosis (85 to 90 % 

 of the polymorphonuclear cells active) and protection of the cells from rup- 

 ture. This serum level is approximately doul:)le the level necessary to pre- 

 vent pathological lesions in the incisor teeth. ^^' ®^ To produce this desir- 

 able degree of phagocytic activity a 300-g. guinea pig would require a 

 daily intake of approximately 6 mg. of the vitamin. As previously stated 

 the ''growth of the odontoblast method" appears to be the best at present 

 available for determining the antiscorbutic requirement, but there is ample 

 reason for the suggestion that the requirement for good health in the sense 

 of controlling infection may be as much as twice that necessary for the 

 prevention of scurvy. However, further study is required under a variety 

 of conditions before a conclusive evaluation can be made of this angle of 

 the vitamin C problem. 



B. OF HUMAN BEINGS 



RICHARD W. VILTER 



The National Research Council has suggested a vitamin C intake of 75 

 to 100 mg. per day for optimum human nutrition. This is the amount 

 necessary to maintain tissue saturation and plasma vitamin C levels of 

 1 mg. % without excessive loss in urine. However, 18 to 25 mg. per day will 

 keep the tissues half saturated and will prevent scurvy. ^^-^^ The League of 

 Nations Technical Commission on Nutrition (1938) and the Vitamin C Sub- 

 committee of the Accessory Food Factors Committee of the British Medical 



60 M. A. Abbasy, L. J. Harris, and P. Ellman, Lancet II, 181 (1937). 



61 E. H. J. Warns, Ned. Tijdschr. Geneesk. 82, 4426 (1938). 



62 0. Dobbelstein, Z. ges. exptl. Med. 107, 532 (1940). 



63 K. Daum, K. Boyd, and W. D. Paul, Proc. Soc. Exptl. Biol. Med. 40, 129 (1939). 

 e-'P^alke, Klin. Wochschr. 18, 818 (1939). 



65 S. L. Osborne and C. J. Farmer, Proc. Soc. Exptl. Biol, ^fcd. 49, 575 (1942). 



66 C. C. Lund, L. A. Shaw, and C. K. Drinker, ./. Exptl. Med. 33, 231 (1921). 



67 J. H. Roe, C. A. Kuether, and R. G. Zimler, /. Clin. Invest. 26, 355 (1947). 



6« 0. H. Lowry, O. A. Bessey, M. J. Brock, and J. A. Lopez, J. Biol. Chem. 166, 111 



(1946). 

 69 W. P. Stamm, T. F. Macrae, and S. Yudkin, Brit. Med. J. 2, 239 (1944). 

 " V. A. Najjar, L. E. Holt, Jr., and H. M. Royston, Bull. Johns Hopkins Hosp. 57, 



315 (1944). 

 " M. Pijoan and E. L. Lozner, Bull. Johns Hopkins Hosp. 73, 303 (1944). 



